Preparation and purification of perylene-3,4-dicarbimides

ABSTRACT

Preparation of perylene-3,4-dicarbimides by reaction of a perylene-3,4,9,10-tetracarboxylic acid or of the corresponding anhydrides with a primary amine by performing the reaction in the presence of a tertiary nitrogen base as solvent and of a transition metal or transition metal salt as catalyst, and purification of perylene-3,4-dicarbimides obtained by reaction of a perylene-3,4,9,10-tetracarboxylic acid or of the corresponding anhydrides with a primary amine by heating the crude products initially in N-methylpyrrolidone and then treating the resulting N-methylpyrrolidone adducts in the presence of an organic diluent with a base, and if desired subjecting the subsequently isolated products to an additional treatment with an aqueous acid, and also novel perylene-3,4-dicarbimides and their use as fluorescent dyes, pigments or pigment additive precursors.

This application is a 371 of PCT/EP96/00167, filed Jan. 12, 1996.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a novel process for preparingperylene-3,4-dicarbimides by reacting aperylene-3,4,9,10-tetracarboxylic acid, or the corresponding anhydrides,with a primary amine.

The invention also relates to a novel process for purifyingperylene-3,4-dicarbimides obained by reaction of aperylene-3,4,9,10-tetracarboxylic acid or of the correspondinganhydrides with a primary amine.

The invention finally relates to novel perylene-3,4-dicarbimides of thegeneral formula Ia ##STR1## where

R^(1') is C₁₄ -C₃₀ -alkyl whose carbon chain may be interrupted by oneor more of --O--, --S--, --NR³ --, --CO-- and/or --SO₂ -- and which maybe monosubstituted or polysubstituted by carboxyl, sulfo, hydroxyl,cyano, C₁ -C₆ -alkoxy or a 5-, 6- or 7-membered heterocyclic radicalwhich is attached via a nitrogen atom and which may contain furtherheteroatoms and may be aromatic, where

R³ is hydrogen or C₁ -C₆ -alkyl;

C₅ -C₈ -cycloalkyl whose carbon skeleton may be interrupted by one ormore of --O--, --S-- and/or --NR³ --; phenyl which is monosubstituted orpolysubstituted by C₁ -C₄ -alkyl or methoxy at least in the two orthopositions, by C₅ -C₁₈ -alkyl, C₂ -C₆ -alkoxy, halogen, hydroxyl, cyano,carboxyl, --CONHR⁴, --NHCOR⁴ and/or aryl- or hetaryl-azo, which may eachbe substituted by C₁ -C₁₀ -alkyl, C₁ -C₆ -alkoxy, halogen, hydroxyl,cyano or carboxyl, where

R⁴ is hydrogen; C₁ -C₁₈ -alkyl; aryl or hetaryl, which may each besubstituted by C₁ -C₆ -alkyl, C₁ -C₆ -alkoxy, halogen, hydroxyl orcyano;

naphthyl or hetaryl, which may each be substituted by the substituentsmentioned for phenyl, in which case the C₁ -C₄ -alkyl and C₁ -C₆ -alkoxysubstituents may be in any desired position on the ring system;

R² is in each instance independently of the other instances hydrogen;halogen; C₁ -C₁₈ -alkyl; aryloxy, arylthio, hetaryloxy or hetarylthio,which may each be substituted by C₁ -C₁₀ -alkyl, C₁ -C₆ -alkoxy, cyanoor carboxyl.

2. Description of the Background

Perylene-3,4-dicarbimides of the formula ##STR2## (A: hydrogen ororganic radical) are known to be suitable for use as intermediates formaking pigment additives, fluorescent dyes and fluorescent pigments(unpublished DE-A-43 25 247; EP-A-596 292; Chimia 48, 503-505 (1994)).

As well as the unsubstituted perylene-3,4-dicarbimide (A=H), only a fewN-alkyl- and N-phenyl-substituted perylene-3,4-dicarbimides (A=methyl,ethyl, n-propyl, n-butyl, isobutyl, n-pentyl, n-hexyl, n-octyl,n-dodecyl, phenyl, 4-tolyl, 4-anisyl, 2,5-di-tert-butylphenyl) are knownso far and they are prepared by complicated, multistage processesstarting from perylene-3,4,9,10-tetracarboxylic dianhydride ##STR3## viathe corresponding perylene-3,4,9,10-tetracarbimide anhydrides ##STR4##in usually unsatisfactory yields and purities which necessitate costlymethods of purification (extraction, column chromatography).

For instance, the unsubstituted and the N-alkyl-substitutedperylene-3,4-dicarbimides are obtained by alkaline decarboxylation ofthe imide-anhydrides at temperatures ≧220° C. under superatmosphericpressure (reaction times of 18 h) (DE-C-486 491; Bulletin of theChemical Society of Japan 54, 1575-1576 (1981); EP-A 596 292). However,this process is only suitable for aliphatic imides which are stable tobases.

To prepare the N-phenyl-, -tolyl- and -anisyl-substituted (as well asN-methyl- and -ethyl-substituted) perylene-3,4-dicarbimides, theinitially prepared unsubstituted perylene-3,4-dicarbimide is sulfonatedwith sulfuric acid, then converted with potassium hydroxide solutioninto the sulfonated anhydride, whch is then reacted with thecorresponding primary amine to form the sulfonated N-substituted imide,which is finally desulfonated with sulfuric acid to the desiredperylene-3,4-dicarbimide (Bulletin of the Chemical Society of Japan 52,1723-1726 (1979), Shikizai Kyokaishi 49, 29-34 (1976) = ChemicalAbstracts 85:209285). This process is very complicated and can only beused for imides which are stable to sulfuric acid.

Finally, it is mentioned in Chimia 48 (1994), 502-505, thatN-(2,5-di-tert-butylphenyl)perylene-3,4-dicarbimide can be obtained bycondensing perylene-3,4,9,10-tetracarboxylic dianhydride with2,5-di-tert-butylaniline in the presence of water. However, thisreaction likewise yields the imide only in a yield of 50%; moreover,only moderately sterically hindered amines can be reacted in this way.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a simple andeconomical process which makes possible the preparation of any desiredperylene-3,4-dicarbimides in good yields. It is a further object todevelop a simple, inexpensive purifying process to which the imideproducts can be subjected, if necessary, to increase their purity.

We have found that the first object is achieved by a process forpreparing perylene-3,4-dicarbimides by reacting aperylene-3,4,9,10-tetracarboxylic acid or the corresponding anhydrideswith a primary amine, which comprises performing the reaction in thepresence of a tertiary nitrogen base as solvent and of a transitionmetal or transition metal salt as catalyst.

We have also found that the second object is achieved by a process forpurifying perylene-3,4-dicarbimides obtained by reaction of aperylene-3,4,9,10-tetracarboxylic acid or of the correspondinganhydrides with a primary amine, which comprises first heating the crudeproducts in N-methylpyrrolidone, then treating the resultingN-methylpyrrolidone adducts with a base in the presence of an organicdiluent, and, if desired, subjecting the subsequently isolated productsto an additional treatment with an aqueous acid.

We have further found a process for making pureperylene-3,4-dicarbimides which comprises combining the process ofpreparation with this process of purification.

Finally, the present invention provides the perylene-3,4-dicarbimides ofthe above-defined formula Ia.

Preferred perylene-3,4-dicarbimides Ia are revealed in the subclaims.

DETAILED DESCRIPTION OF THE INVENTION

The process of the invention is suitable for preparing any9,10-unsubstituted perylene-3,4-dicarbimides. Examples of advantageouslyobtainable perylene-3,4-dicarbimides have the general formula I ##STR5##where

R¹ is hydrogen;

C₁ -C₃₀ -alkyl whose carbon chain may be interrupted by one or more of--O--, --S--, --NR³ --, --CO-- and/or --SO₂ -- and which may bemonosubstituted or polysubstituted by carboxyl, sulfo, hydroxyl, cyano,C₁ -C₆ -alkoxy or a 5-, 6- or 7-membered heterocyclic radical which isattached via a nitrogen atom and which may contain further heteroatomsand may be aromatic, where

R³ is hydrogen or C₁ -C₆ -alkyl;

C₅ -C₈ -cycloalkyl whose carbon skeleton may be interrupted by one ormore of --O--, --S-- and/or --NR³ --; aryl or hetaryl, which may each bemonosubstituted or polysubstituted by C₁ -C₁₈ -alkyl, C₁ -C₆ -alkoxy,halogen, hydroxyl, cyano, carboxyl, --CONHR⁴, --NHCOR⁴ or aryl- and/orhetaryl-azo, which may each be substituted by C₁ -C₁₀ -alkyl, C₁ -C₆-alkoxy, halogen, hydroxyl, cyano or carboxyl, where

R⁴ is hydrogen; C₁ -C₁₈ -alkyl; aryl or hetaryl, which may each besubstituted by C₁ -C₆ -alkyl, C₁ -C₆ -alkoxy, halogen, hydroxyl orcyano;

R² is in each instance independently of the other instances hydrogen;halogen; C₁ -C₁₈ -alkyl; aryloxy, arylthio, hetaryloxy or hetarylthio,which may each be substituted by C₁ -C₁₀ -alkyl, C₁ -C₆ -alkoxy, cyanoor carboxyl.

The process of the invention has particular importance for preparing thenovel and preferred perylene-3,4-dicarbimides Ia which are defined inthe introduction and subclaims.

For instance, amines having a relatively high alkyl chain length(generally >C₁₂), which would render the imides insoluble in the aqueousreaction media used in the known processes, amines with modified and/orsubstituted alkyl chains and also aromatic radicals, which would not bestable under the strongly basic or acid reaction conditions previouslyused, and especially sterically hindered aromatic amines, in particularo,o'-disubstituted anilines, which can likewise not be used in the knownprocesses, are easy to react with the appropriateperylene-3,4,9,10-tetracarboxylic acids or anhydrides, in particulardianhydrides, which carry the substituents R².

Any alkyl appearing in the formulae I and Ia may be straight-chain orbranched. Substituted aryl may generally include up to 3, preferably 1or 2, of the substituents mentioned.

Specific examples of suitable radicals R¹ and R² (and of theirsubstituents) are:

methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl,tert-butyl, pentyl, isopentyl, neopentyl, tert-pentyl, hexyl,2-methylpentyl, heptyl, 1-ethylpentyl, octyl, 2-ethylhexyl, isooctyl,nonyl, isononyl, decyl, isodecyl, undecyl, dodecyl, tridecyl,isotridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl,nonadecyl and eicosyl (the above designations isooctyl, isononyl,isodecyl and isotridecyl are trivial names derived from the oxo processalcohols--cf. Ullmann's Encyklopadie der technischen Chemie, 4thedition, volume 7, pages 215 to 217, and volume 11, pages 435 and 436);

2-methoxyethyl, 2-ethoxyethyl, 2-propoxyethyl, 2-isopropoxyethyl,2-butoxyethyl, 2- and 3-methoxypropyl, 2- and 3-ethoxypropyl, 2- and3-propoxypropyl, 2- and 3-butoxypropyl, 2- and 4-methoxybutyl, 2- and4-ethoxybutyl, 2- and 4-propoxybutyl, 3,6-dioxaheptyl, 3,6-dioxaoctyl,4,8-dioxanonyl, 3,7-dioxaoctyl, 3,7-dioxanonyl, 4,7-dioxaoctyl,4,7-dioxanonyl, 2- and 4-butoxybutyl, 4,8-dioxadecyl, 3,6,9-trioxadecyl,3,6,9-trioxaundecyl, 3,6,9-trioxadodecyl, 3,6,9,12-tetraoxatridecyl and3,6,9,12-tetraoxatetradecyl;

2-methylthioethyl, 2-ethylthioethyl, 2-propylthioethyl,2-isopropylthioethyl, 2-butylthioethyl, 2- and 3-methylthiopropyl, 2-and 3-ethylthiopropyl, 2- and 3-propylthiopropyl, 2- and3-butylthiopropyl, 2- and 4-methylthiobutyl, 2- and 4-ethylthiobutyl, 2-and 4-propylthiobutyl, 3,6-dithiaheptyl, 3,6-dithiaoctyl,4,8-dithianonyl, 3,7-dithiaoctyl, 3,7-dithianonyl, 4,7-dithiaoctyl,4,7-dithianonyl, 2- and 4-butylthiobutyl, 4,8-dithiadecyl,3,6,9-trithiadecyl, 3,6,9-trithiaundecyl, 3,6,9-trithiadodecyl,3,6,9,12-tetrathiatridecyl and 3,6,9,12-tetrathiatetradecyl;

2-monomethyl- and 2-monoethylaminoethyl, 2-dimethylaminoethyl, 2- and3-dimethylaminopropyl, 3-monoisopropylaminopropyl, 2- and4-monopropylaminobutyl, 2- and 4-dimethylaminobutyl,6-methyl-3,6-diazaheptyl, 3,6-dimethyl-3,6-diazaheptyl, 3,6-diazaoctyl,3,6-dimethyl-3,6-diazaoctyl, 9-methyl-3,6,9-triazadecyl,3,6,9-trimethyl-3,6,9-triazadecyl, 3,6,9-triazaundecyl,3,6,9-trimethyl-3,6,9-triazaundecyl, 12-methyl-3,6,9,12-tetraazatridecyland 3,6,9,12-tetramethyl-3,6,9,12-tetraazatridecyl;

propan-2-on-1-yl, butan-3-on-1-yl, butan-3-on-2-yl and2-ethylpentan-3-on-1-yl;

2-methylsulfonylethyl, 2-ethylsulfonylethyl, 2-propylsulfonylethyl,2-isopropylsulfonylethyl, 2-butylsulfonylethyl, 2- and3-methylsulfonylpropyl, 2- and 3-ethylsulfonylpropyl, 2- and3-propylsulfonylpropyl, 2- and 3-butylsulfonylpropyl, 2- and4-methylsulfonylbutyl, 2- and 4-ethylsulfonylbutyl, 2- and4-propylsulfonylbutyl and 4-butylsulfonylbutyl;

carboxymethyl, 2-carboxyethyl, 3-carboxypropyl, 4-carboxybutyl,5-carboxypentyl, 6-carboxyhexyl, 8-carboxyoctyl, 10-carboxydecyl,12-carboxydodecyl and 14-carboxytetradecyl;

sulfomethyl, 2-sulfoethyl, 3-sulfopropyl, 4-sulfobutyl, 5-sulfopentyl,6-sulfohexyl, 8-sulfooctyl, 10-sulfodecyl, 12-sulfododecyl and14-sulfotetradecyl;

2-hydroxyethyl, 2-hydroxypropyl, 1-hydroxyprop-2-yl, 2- and4-hydroxybutyl, 1-hydroxybut-2-yl and 8-hydroxy-4-oxaoctyl,2-cyanoethyl, 3-cyanopropyl, 2-methyl-3-ethyl-3-cyanopropyl,7-cyano-7-ethylheptyl and 4-methyl-7-methyl-7-cyanoheptyl;

methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, sec-butoxy,tert-butoxy, pentoxy, isopentoxy, neopentoxy, tert-pentoxy and hexoxy;

carbamoyl, methylaminocarbonyl, ethylaminocarbonyl, ropylaminocarbonyl,butylaminocarbonyl, pentylaminocarbonyl, hexylaminocarbonyl,heptylaminocarbonyl, octylaminocarbonyl, nonylaminocarbonyl,decylaminocarbonyl and phenylaminocarbonyl;

formylamino, acetylamino, propionylamino and benzoylamino; chlorine,bromine and iodine;

phenylazo, 2-naphthylazo, 2-pyridylazo and 2-pyrimidylazo;

cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, 2-dioxanyl,4-morpholinyl, 2- and 3-tetrahydrofuryl, 1-, 2- and 3-pyrrolidinyl and1-, 2-, 3- and 4-piperidyl;

phenyl, 2-naphthyl, 2- and 3-pyrryl, 2-, 3- and 4-pyridyl, 2-, 4- and5-pyrimidyl, 3-, 4- and 5-pyrazolyl, 2-, 4- and 5-imidazolyl, 2-, 4- and5-thiazolyl, 3-(1,2,4-triazyl), 2-(1,3,5-triazyl)., 6-quinaldyl, 3-, 5-,6- and 8-quinolinyl, 2-benzoxazolyl, 2-benzothiazolyl,5-benzothiadiazolyl, 2- and 5-benzimidazolyl and 1- and 5-isoquinolyl;

2-, 3- and 4-methylphenyl, 2,4-, 3,5- and 2,6-dimethylphenyl,2,4,6-trimethylphenyl, 2-, 3- and 4-ethylphenyl, 2,4-, 3,5- and2,6-diethylphenyl, 2,4,6-triethylphenyl, 2-, 3- and 4-propylphenyl,2,4-, 3,5- and 2,6-dipropylphenyl, 2,4,6-tripropylphenyl, 2-, 3- and4-isopropylphenyl, 2,4-, 3,5- and 2,6-diisopropylphenyl,2,4,6-triisopropylphenyl, 2-, 3- and 4-butylphenyl, 2,4-, 3,5- and2,6-dibutylphenyl, 2,4,6-tributylphenyl, 2-, 3- and 4-isobutylphenyl,2,4-, 3,5 and 2,6-diisobutylphenyl, 2,4,6-triisobutylphenyl, 2-, 3- and4-sec-butylphenyl, 2,4-, 3,5- and 2,6-di-sec-butylphenyl and2,4,6-tri-sec-butylphenyl; 2-, 3- and 4-methoxyphenyl, 2,4-, 3,5- and2,6-dimethoxyphenyl, 2,4,6-trimethoxyphenyl, 2-, 3- and 4-ethoxyphenyl,2,4-, 3,5- and 2,6-diethoxyphenyl, 2,4,6-triethoxyphenyl, 2-, 3- and4-propoxyphenyl, 2,4-, 3,5- and 2,6-dipropoxyphenyl, 2-, 3- and4-isopropoxyphenyl, 2,4- and 2,6-diisopropoxyphenyl and 2-, 3- and4-butoxyphenyl; 2-, 3- and 4-chlorophenyl and 2,4-, 3,5- and2,6-dichlorophenyl; 2-, 3- and 4-hydroxyphenyl and 2,4-, 3,5- and2,6-dichlorophenyl; 2-, 3- and 4-hydroxyphenyl and 2,4-, 3,5- and2,6-dihydroxyphenyl; 2-, 3- and 4-cyanophenyl; 3- and 4-carboxyphenyl;3- and 4-carboxyamidophenyl, 3- and 4-N-methylcarboxamidophenyl and 3-and 4-N-ethylcarboxamidophenyl; 3- and 4-acetylaminophenyl, 3- and4-propionylaminophenyl and 3- and 4-butyrylaminophenyl; 3- and4-N-phenylaminophenyl, 3- and 4-N-(o-tolyl)aminophenyl, 3- and4-N-(m-tolyl)aminophenyl and 3- and 4-(p-tolyl)aminophenyl; 3- and4-(2-pyridyl)aminophenyl, 3- and 4-(3-pyridyl)aminophenyl, 3- and4-(4-pyridyl)aminophenyl, 3- and 4-(2-pyrimidyl)aminophenyl and 4-(4-pyrimidyl) aminophenyl;

4-phenylazophenyl, 4-(1-naphthylazo)phenyl, 4-(2-naphthylazo)phenyl,4-(4-naphthylazo)phenyl, 4-(2-pyridylazo)phenyl, 4-(3-pyridylazo)phenyl,4-(4-pyridylazo)phenyl, 4-(2-pyrimidylazo)phenyl,4-(4-pyrimidylazo)phenyl and 4-(5-pyrimidylazo)phenyl;

phenoxy, phenylthio, 2-naphthoxy, 2-naphthylthio, 2-, 3- and4-pyridyloxy, 2-, 3- and 4-pyridylthio, 2-, 4- and 5-pyrimidyloxy and2-, 4- and 5-pyrimidylthio.

The process of the present invention for preparingperylene-3,4-dicarbimides starts from appropriately substitutedperylene-3,4,9,10-tetracarboxylic acids and anhydrides, in particulardianhydrides, which can in turn be obtained by halogenation and ifdesired subsequent replacement of the halogen atoms by aryloxy,arylthio, hetaryloxy, hetarylthio or alkyl radicals.

The particularly interesting, 1,7-disubstitutedperylene-3,4,9,10-tetracarboxylic acids and anhydrides are as describedin German Patent Applications 195 47 209.8 and 195 47 210.1 obtainableby a multistage process starting from1,7-dibromoperylene-3,4,9,10-tetracarboxylic acid or dianhydrideprepared by selective bromination of perylene-3,4,9,10-tetracarboxylicacid or dianhydride in 100% strength by weight sulfuric acid at from 80°to 90° C. These are reacted in the presence of a polar aprotic solventsuch as N-methylpyrrolidone and optionally of an imidation catalyst, forexample of an organic or inorganic acid or of a transition metal salt,with a primary amine to form the corresponding1,7-dibromoperylene-3,4,9,10-tetracarboxylic diimide, which is thenreacted either in the presence of an inert aprotic solvent such asN-methylpyrrolidone or of a nonnucleophilic or only weakly nucleophilicbase, for example sodium carbonate or potassium carbonate, with anaromatic alcohol or thioalcohol or else in the presence of an aproticsolvent such as tetrahydrofuran, of a palladium complex as catalyst andof a copper salt as cocatalyst and of a base, for example piperidine,with a 1-alkyne. In the last case, 1,7-disubstitutedperylene-3,4,9,10-tetracarboxylic diimides are obtained which containunsaturated bonds in the substituent R² which are reducible bysubsequent stirring in a hydrogen atmosphere or by catalytic reductionwith hydrogen. In a last reaction step, the either 1,7-diaroxy-,-diarylthio- or -dialkyl-substituted perylene-3,4,9,10-tetracarboxylicdiimide is then saponified in the presence of a polar protic solventsuch as isopropanol and of a base, for example sodium hydroxide orpotassium hydroxide, to the 1,7-disubstitutedperylene-3,4,9,10-tetracarboxylic acid or dianhydride.

In the novel preparation process, the perylene-3,4,9,10-tetracarboxylicacids or their anhydrides, in particular the dianhydrides, are reactedwith the desired primary amines (especially R¹ -NH₂) in the presence ofa tertiary nitrogen base as solvent and of a transition metal ortransition metal salt as catalyst.

This gives rise not only to a unilateral condensation (imidation)reaction but also to a unilateral decarboxylation.

Suitable solvents are in particular those tertiary nitrogen bases whosemelting points are below room temperature, since this facilitatesreaction mixture workup and solvent recovery.

Examples of suitable bases are cyclic imides such asN-methylpyrrolidone, tertiary aliphatic amines NR³ whose alkyl radicalsR have from 4 to 8 carbon atoms, such as trihexylamine, and inparticular aromatic heterocycles such as quinaldine, isoquinoline and inparticular quinoline.

The amount of solvent is not critical per se; it will usually range from2 to 20 kg, preferably from 6 to 12 kg, of solvent per kg ofperylene-3,4,9,10-tetracarboxylic dianhydride.

Suitable catalysts are in particular the transition metals iron andespecially zinc and copper and also in particular their inorganic andorganic salts, which are preferably used in anhydrous form.

Examples of preferred salts are copper(I) oxide, copper(II) oxide,copper(I) chloride, copper(II) acetate, zinc acetate and zincpropionate.

It is of course also possible to use mixtures of the catalystsmentioned.

Typically from 5 to 80% by weight of catalyst are used, based on theperylene-3,4,9,10-tetracarboxylic dianhydride. Preferred amounts rangefrom 10 to 25% by weight in the case of the copper compounds and from 40to 60% by weight in the case of the zinc salts, likewise based on theanhydride.

Suitable primary amines for the preparation process of the inventioninclude all primary amines which are stable at the reaction temperature,preferably those whose boiling point at the reaction pressure is abovethe reaction temperature.

The reaction temperature is generally from 120° to 250° C., inparticular from 170° to 235° C. It is advisable to work under aprotective gas atmosphere (eg. nitrogen).

The preparation process of the invention can be carried out atatmospheric pressure or at a superatmospheric pressure of customarily upto 10 bar. The superatmospheric option is advantageous in particular inthe case of volatile amines (ie. where the boiling point is ≦ about 180°C.).

In general, the molar ratio of the starting compounds amine andanhydride is from 0.8:1 to 6:1. For the atmospheric reaction it ispreferably from 0.8:1 to 1.2:1, whereas for the superatmosphericreaction it is in particular from 2:1 to 4:1.

The reaction of the invention is customarily complete within 2-30 h,especially within 3-12 h.

The atmospheric process is advantageously carried out as follows:

Perylene-3,4,9,10-tetracarboxylic dianhydride and catalyst are initiallycharged in part of the solvent quantity (eg. about half), the apparatusis flushed with nitrogen (about 15 min), the mixture is heated to thereaction temperature under stirring, and a solution of the primary aminein the remaining solvent is added dropwise over about 2-6 h. Following asubsequent stirring time of customarily about 0.5-8 h at the reactiontemperature, the batch is cooled down to 120°-140° C., and unconvertedanhydride and the bulk of the catalyst are filtered off at thattemperature.

The rest of the workup of the filtrate, cooled down to room temperature,for the (crude) products (perylene-3,4-dicarbimide contaminated byvarying amounts of diimide) can be carried out in a conventional mannerby, if necessary after addition of primary alcohols such as methanol tocomplete the precipitation, filtering off the precipitated products andwashing and drying them.

In the case of the preparation of perylene-3,4-dicarbimides which are nolonger soluble in the solvent at temperatures ≦ about 140° C. (eg.N-(4-phenylazophenyl)perylene-3,4-dicarbimide), these imides areadvantageously filtered off at that temperature, the filter cake iswashed preferably with hot (likewise about 130° C.) solvent andmethanol, and the washed filter cake is boiled for from 0.5 to 1 h indilute inorganic acid (for example 10-15% strength by weighthydrochloric acid) for complete removal of the catalyst. Subsequentlythe imides can be isolated in a conventional manner by filtration of thecooled mixture, washing with water until the wash liquor runoff isneutral and salt-free, and drying.

Generally, the products thus treated are already sufficiently pure(>95%) as to require no further purification.

The superatmospheric process is advantageously carried out by initiallycharging perylene-3,4,9,10-tetracarboxylic dianhydride, catalyst andprimary amine in all of the solvent, flushing the pressure apparatuswith nitrogen (about 15 min), closing the pressure apparatus, setting anitrogen pressure of generally 1-2 bar, and then heating the stirredmixture to the reaction temperature and maintaining it at thattemperature for about 6-8 h. After cooling down to customarily 120°-140°C. and decompressing, the reaction mixture can be worked up as describedabove.

If the (crude) products obtained in the preparation process of theinvention do not meet the desired purity requirements (the productsobtained generally have purities ≧80%), they can additionally besubjected to the purification process of the invention.

In the purification process of the invention, the crudeperylene-3,4-dicarbimide products are initially heated inN-methylpyrrolidone (NMP) to convert them into NMP adducts. If the imidewas prepared using NMP as solvent, this step can of course be omitted.

The NMP adducts are subsequently subjected to an alkaline purificationtreatment. If desired, it can be followed by an acid aftertreatment.

The first step of the purification process of the invention, theformation of the NMP adducts, is customarily carried out by heating thedried crude product in about 3-10 times, preferably 5.5-6.5 times, theweight of NMP, with stirring to about 140°-200° C., preferably 160°-180°C., particularly preferably 165°-170° C., generally maintaining thistemperature for 10-60 min, in particular 15-30 min. This treatment isadvantageously carried out under protective gas (eg. nitrogen).

Advantageously the mixture is then cooled down, preferably with slowstirring, initially to about 50°-55° C. and then without stirring toroom temperature.

The NMP adduct can then be isolated in a conventional manner byfiltration, washing (preferably first with a mixture of NMP andwater-soluble alcohol such as ethanol, then with dilute hydrochloricacid, and finally with water) with or without drying.

The second step of the purification process of the invention, thealkaline treatment of the NMP adduct, is advantageously carried out inthe precence of an organic reaction medium.

Suitable organic diluents include not only inert aromatic solvents suchas toluene and xylene but also, with preference, alcohols which can bemonohydric or polyhydric, for example aromatic alcohols such as phenoland benzyl alcohol and aliphatic alcohols, not only glycols and glycolethers, such as ethylene glycol, propylene glycol and butylglycol(ethylene glycol monobutyl ether) but also, in particular, C₂ -C₆-alcohols such as ethanol, propanol, butanol, pentanol and hexanol,which each may also be branched, such as, preferably, isopropanol.

In general, the diluent is used in an amount of from 40 to 200 kg, inparticular from 80 to 120 kg, per kg of NMP adduct.

Suitable bases include not only sterically hindered nitrogen bases, suchas diazabicycloundecene and diazabicyclo 2.2.2!octane, but especiallyalkali metal hydroxides, such as sodium hydroxide and in particularpotassium hydroxide, and alkali metal salts of secondary and tertiaryaliphatic (preferably C₃ -C₆) alcohols, such as sodium tert-butoxide andin particular potassium tert-butoxide.

The alkali metal hydroxides are advantageously used together with water(for example from 40 to 60% by weight, based on the alkali metalhydroxide).

It is customary to use from 2 to 15 kg of base per kg of NMP adduct,preferably from 5 to 7 kg, in particular about 6 kg, of dry alkali metalhydroxide or from 0.5 to 1.5 kg, in particular from 0.7 to 1 kg, ofalkoxide or nitrogen base.

It is advisable to carry out the alkaline treatment at elevatedtemperature. The treatment temperature is generally from 50° to 150° C.,preferably from 60° to 120° C.

An advantageous procedure is to charge the diluent initially, add theNMP adduct and the base, and then heat the mixture with stirring to thetreatment temperature, maintaining said temperature for about 1-24 h, inparticlar 1-10 h.

The purified product can be isolated in a conventional manner by coolingto about 25°-30° C., if necessary completing the precipitation by addingmethanol, filtering off the precipitate, washing the filter cake(preferably with the diluent used for the purification, methanol andwater) and drying.

If desired, it is possible to follow this up with an additional acidtreatment by suspending the undried filter cake in a dilute inorganicacid, for example 4-6% strength by weight hydrochloric acid (about 4-6kg of acid per kg of filter cake).

The purified imide can then be isolated in a conventional manner byfiltration, washing with water (until the wash liquor running off isneutral) and drying.

The additional acid treatment is advisable in particular in the case ofperylene-3,4-dicarbimides of the formula I where R¹ is phenyl or C₁ -C₄-alkyl-substituted phenyl and R² is hydrogen.

The novel process for making pure perylene-3,4-dicarbimides constitutesan advantageous combination of the preparation process of the inventionwith the purifying process of the invention. It yields any desiredperylene-3,4-dicarbimides in a technically simple and economical mannerin excellent purities (generally >98%) and good yields (generally60-90%).

The novel perylene-3,4-dicarbimides Ia, as well as the imides I preparedaccording to the invention, are advantageously useful not only aspigment additive precursors but also as pigments or fluorescent dyes.They can be used in particular for coloring macromolecular organicmaterials or else organic/inorganic composites.

Suitable pigments are in particular the perylene-3,4-dicarbimides Iawhere R^(1') is phenyl or monocyclic hetaryl (in particular pyridyl orpyrimidyl), which is each monosubstituted, disubstituted ortrisubstituted by C₁ -C₄ -alkyl and/or cyano or monosubstituted byphenylazo or naphthylazo, and R² is hydrogen.

Suitable fluorescent dyes are in particular theperylene-3,4-dicarbimides Ia where R^(1') is phenyl or monocyclichetaryl (in particular pyridyl or pyrimidyl), which is in each casemonsubstituted, disubstituted or trisubstituted by hydroxyl, carboxyl,--CONHR⁴ and/or --NHCOR⁴ (R⁴ : C₁ -C₄ -alkyl or phenyl which may besubstituted by C₁ -C₄ -alkyl or C₁ -C₄ -alkoxy), or C₅ -C₈ -cycloalkyl,and R² is hydrogen or phenoxy which may be monosubstituted,disubstituted or trisubstituted by C₁ -C₄ -alkyl.

EXAMPLES A) Preparation of perylene-3,4-dicarbimides of the formula Ib##STR6## from the corresponding perylene-3,4,9,10-tetracarboxylicdianhydrides of the formula II ##STR7##

The 1,7-disubstituted perylene-3,4,9,10-tetracarboxylic dianhydrides IIused as starting material for the 1,7-disubstitutedperylene-3,4-dicarbimides (Examples 25 to 27) were prepared as follows.

a) Preparation of 1,7-dbromoperylene-3,4,9,10-tetracarboxylicdianhydride (IIa) Example 1

A mixture of 292.5 g (0.75 mol) of perylene-3,4,9,10-tetracarboxylicdianhydride (purity >98%) and 4420 g of 100% strength by weight sulfuricacid was heated to 85° C. following stirring for 12 hours and subsequentaddition of 7 g of iodine. 262.5 g (1.64 mol) of bromine were then addeddropwise over 8 h.

After cooling down to room temperature and displacing the excess bromineby nitrogen, the sulfuric acid concentration of the reaction mixture wasreduced to 86% by weight by adding a total of 670 g of water a little ata time over 1 h. After cooling the reaction mixture, which had heated upto 85° C. in the course of the addition, to room temperature, theprecipitated product was filtered off on a G4 glass frit, washed with 3kg of 86% strength by weight sulfuric acid, then suspended in 5 l ofwater, filtered off again, washed neutral and dried under reducedpressure at 120° C.

This gave 370 g of IIa in the form of a luminously red, finelycrystalline powder having a melting point >360° C. and a purity >98%,which corresponds to a yield of 90%.

b) Preparation ofN,N'-dicyclohexyl-1,7-dibromoperylene-3,4,9,10-tetracarboxylic diimide(III) ##STR8## Example 2

To a mixture of 69.9 g (127 mmol) of1,7-dibromoperylene-3,4,9,10-tetracarboxylic dianhydride (IIa)(Example 1) in 900 ml of N-methyl-2-pyrrolidone were initially addedwith stirring 42.8 g of glacial acetic acid and then, a little at atime, a total of 381 mmol of cyclohexylamine. The reaction mixture wasthen heated under nitrogen to 85° C. and stirred at that temperature for6 h.

After cooling down to room temperature, the precipitated reactionproduct was filtered off, washed with a total of 2 l of methanol anddried under reduced pressure at 100° C.

This gave 75.1 g of IVa as a bright red, microcrystalline powder havinga melting point >360° C. and a purity of 97%, which corresponds to ayield of 83%.

Analytical data: Elemental analysis (% by weight calc./obs.): C:60.7/60.3; H: 4.0/4.2; N: 3.9/3.8; O: 9.0/9.3; Br: 22.4/22.0; IR (KBr):ν=1698 (s, C═O), 1655 (s, C═O) cm⁻¹ ; UV/VIS (CHCl₃): λ_(max) (ε)=491(33411), 526 (50033) nm.

c) Preparation of 1,7-diaroxy-substitutedN,N'-dicyclohexylperylene-3,4,9,10-tetracarboxylic diimides IV ##STR9##Examples 3 and 4

14.25 g (20 mmol) ofN,N'-dicyclohexyl-1,7-dibromoperylene-3,4,9,10-tetracarboxylic diimide(III) from Example 2 were added with stirring to 450 ml ofN-methylpyrrolidone, successively admixed with 6.4 g (46 mmol) ofanhydrous potassium carbonate and a g (40 mmol) of the hydroxyaromaticR² -H, and heated under nitrogen at 120° C. for 1.5 h.

After cooling down to room temperature, the reaction mixture was addedwith stirring to 1.5 l of 6% strength by weight hydrochloric acid. Theprecipitated reaction product was filtered off, washed neutral withwater and dried under reduced pressure at 100° C.

Further details concerning these experiments and their results arecollated in Table 1.

                                      TABLE 1                                     __________________________________________________________________________                      Result                                                                 Hydroxy-                                                                             Yield                                                                             Purity       m.p.                                       Ex.                                                                             R.sup.2                                                                              a g                                                                             aromatic R.sup.2 -H                                                                   g!/ %!                                                                            %! Appearance                                                                              °C.!                               __________________________________________________________________________    3 Phenoxy                                                                              3.8                                                                             Phenol 14.5/98                                                                           93  dark red, crystalline                                                                  >360                                       4 p-tert-                                                                              6.0                                                                             p-tert-Butyl-                                                                        16.0/94                                                                           95  magenta, micro-                                                                        >360                                         Butylphenoxy                                                                           phenol         crystalline                                         __________________________________________________________________________

Analytical data to Example 3:

Elemental analysis (% by weight calc./obs.): C: 78.0/77.5; H: 5.2/5.3;N: 3.8/3.7; O: 13.0/13.4; Mass (FD): m/z=738 (M⁺, 100%); IR (KBr):ν=1695 (s, C═O), 1654 (s, C═O) cm⁻¹ ; UV/VIS (CHCl₃): λ_(max) (ε)=401(7455), 513 (37102), 549 (55004) nm.

Analytical data to Example 4:

Elemental analysis (% by weight calc./obs.): C: 79.0/78.8; H: 6.4/6.4;N: 3.3/3.2; O: 11.3/11.4; Mass (FD): m/z=850 (M⁺, 100%); IR (KBr):ν=1697 (s, C═O), 1654 (s, C═O) cm⁻¹ ; UV/VIS (CHCl₃): λ_(max) (ε)=404(9447), 512 (34785), 547 (52117) nm.

d) Preparation of 1,7-diaroxy-substitutedperylene-3,4,9,10-tetracarboxylic dianhydrides II ##STR10## Examples 5and 6

A mixture of, in each case, 10 g of theN,N'-dicyclohexyl-1,7-diaroxyperylene-3,4,9,10-tetracarboxylic diimide(IV) of Example 3 or 4, 1 l of isopropanol, 65 g of potassium hydroxideand 26 g of water was refluxed for 5 h.

After cooling down to room temperature, the precipitated reactionproduct was filtered off, washed with isopropanol to a colorlessrun-off, then added with stirring to 1 l of 10% strength by weighthydrochloric acid and briefly heated to the boil. After cooling down toroom temperature, the product was again filtered off, washed neutralwith water and dried under reduced pressure at 100° C.

Further details of these experiments and their results are collated inTable 2. The purity of the products was determined by UV/VISspectroscopy and semiquantitative thin layer chromatography over silicagel using trichloroacetic acid/toluene as mobile phase.

                                      TABLE 2                                     __________________________________________________________________________                    Result                                                                  Diimide IV                                                                          Yield                                                                             Purity      m.p.                                          Ex.                                                                              R.sup.2                                                                              of Ex.                                                                               g!/ %!                                                                            %! Appearance                                                                             °C.!                                  __________________________________________________________________________    5  Phenoxy                                                                              3     7.4/94                                                                            98  reddish violet,                                                                       >360                                                                  microcrystalline                                      6  p-tert-                                                                              4     7.7/95                                                                            98  reddish violet,                                                                       >360                                             Butylphenoxy         amorphous                                             __________________________________________________________________________

Analytical data to Example 5:

Elemental analysis (% by weight calc./obs.) C: 75.0/74.8; H: 2.8/2.8; O:22.2/22.3; IR (KBr): ν=1758 (s, C═O), 1729 (s, C═O) cm⁻¹ ; UV/VIS (H₂SO₄): λ_(max) (ε)=415 (8832), 559 (38103) nm.

Analytical data to Example 6: Elemental analysis (% by weightcalc./obs.) C: 76.7/76.6; H: 4.7/4.7; O: 18.6/18.7; IR (KBr): ν=1755 (s,C═O), 1730 (s, C═O); UV/VIS (H₂ SO₄): λ_(max) (ε)=412 (9405), 561(32746) nm.

Examples 7 to 27 1) Preparation Under Atmospheric Pressure (Method M1)

A suspension of 50 mmol of perylene-3,4,9,10-tetracarboxylic dianhydrideII and x g of catalyst K in 100 ml of quinoline was heated with stirringto T°C. under nitrogen. Then a solution of 50 mmol (Example 22: 55 mmol;Example 23: 52 mmol) of the primary amine R¹ NH₂ in 80-100 ml ofquinoline was added dropwise over 3-3.5 h (Examples 7, 8 and 24: 6 h).

Following a subsequent stirring time of t h at T°C., the batch wascooled down to about 130° C. and filtered through a preheated G4 glassfrit. After cooling the filtrate down to room temperature, theprecipitated crude product was filtered off, washed with methanol anddried under reduced pressure. Methanol was carefully added to thefiltrate to complete the precipitation, and the precipitated, morecontaminated crude product was isolated as described above and combinedwith the bulk quantity.

In Example 23, the crude product, which actually came down as aprecipitate at 130°-140° C., was filtered off, washed initially with alittle hot quinoline at 130° C. and then with methanol, and subsequentlyheated in 500 ml of 10% strength by weight hydrochloric acid at 80° C.for 0.5 h with stirring. The hot suspension was filtered, and the filtercake was washed neutral and salt-free with water and likewise driedunder reduced pressure.

2) Preparation Under Superatmospheric Pressure (Method M2)

In a 1 l stirred autoclave, a mixture of 0.2 mol (78.4 g) ofperylene-3,4,9,10-tetracarboxylic dianhydride, x g of catalyst K, 0.6mol of the primary amine R¹ NH₂, and 400 ml of quinoline was flushedwith nitrogen for 15 min. After the autoclave had been sealedpressure-tight, a pressure of 2 bar of nitrogen was preset and theautoclave was then heated to T°C.

Following a subsequent stirring time of t h at T°C. and asuperatmospheric pressure of more than 3 bar, the contents were cooleddown to about 130° C., decompressed and worked up as described ingeneral terms in connection with method M1.

Further details of these experiments and their results are summarized inTable 3.

                                      TABLE 3                                     __________________________________________________________________________                                        Crude yield in                                                                       Purity in                          Ex.                                                                             R.sup.1   R.sup.2                                                                            x g                                                                              K       M T°C.                                                                      t h                                                                              % (based on II)                                                                      %                                  __________________________________________________________________________     7                                                                              2,6-Diisopropylphenyl                                                                   H    3.6                                                                              Copper(I) oxide                                                                       M1                                                                              230                                                                              2.5                                                                              79     90                                  8                                                                              2,6-Diisopropylphenyl                                                                   H    9.8                                                                              Zinc propionate                                                                       M1                                                                              230                                                                              4.5                                                                              75     85                                  9                                                                              2,6-Diisopropylphenyl                                                                   H    9.8                                                                              Zinc acetate                                                                          M1                                                                              230                                                                              4.0                                                                              72     85                                 10                                                                              2,6-Diisopropylphenyl                                                                   H    12.0                                                                             Copper(I) oxide                                                                       M2                                                                              200                                                                              9.0                                                                              70     80                                 11                                                                              Phenyl    H    16.2                                                                             Zinc propionate                                                                       M1                                                                              230                                                                              11.0                                                                             94     80                                 12                                                                              Phenyl    H    16.2                                                                             Zinc acetate                                                                          M1                                                                              230                                                                              7.0                                                                              92     85                                 13                                                                              Phenyl    H    2.9                                                                              Copper(I) oxide                                                                       M1                                                                              200                                                                              1.0                                                                              84     85                                 14                                                                              2-Methylphenyl                                                                          H    2.0                                                                              Copper(I) oxide                                                                       M1                                                                              200                                                                              1.5                                                                              78     85                                 15                                                                              2,4,6-Trimethylphenyl                                                                   H    16.2                                                                             Zinc propionate                                                                       M1                                                                              230                                                                              5.5                                                                              89     80                                 16                                                                              2-Pyridyl H    2.0                                                                              Copper(I) oxide                                                                       M1                                                                              200                                                                              1.0                                                                              73     80                                 17                                                                              2-Pyrimidyl                                                                             H    16.2                                                                             Zinc propionate                                                                       M1                                                                              230                                                                              3.0                                                                              79     90                                 18                                                                              4-Acetylaminophenyl                                                                     H    2.9                                                                              Copper(I) oxide                                                                       M1                                                                              200                                                                              2.0                                                                              91     90                                 19                                                                              5-Nonyl   H    2.0                                                                              Copper(I) oxide                                                                       M1                                                                              200                                                                              1.5                                                                              86     75                                 20                                                                              Dodecyl   H    16.2                                                                             Zinc acetate                                                                          M1                                                                              230                                                                              6.0                                                                              60     90                                 21                                                                              Dodecyl   H    2.0                                                                              Copper(I) oxide                                                                       M1                                                                              180                                                                              1.0                                                                              70     80                                 22                                                                              Octadecyl H    16.2                                                                             Zinc acetate                                                                          M1                                                                              230                                                                              5.5                                                                              57     90                                 23                                                                              4-Phenylazophenyl                                                                       H    2.0                                                                              Copper(I) oxide                                                                       M1                                                                              180                                                                              1.5                                                                              79     >99                                24                                                                              3,5-Dimethylphenyl                                                                      H    3.2                                                                              Copper(I) oxide                                                                       M1                                                                              200                                                                              2.0                                                                              89     85                                 25                                                                              2,6-Diisopropylphenyl                                                                   Br   3.0                                                                              Copper(I) oxide                                                                       M1                                                                              200                                                                              1.0                                                                              82     90                                 26                                                                              3,5-Dimethylphenyl                                                                      Phenoxy                                                                            3.0                                                                              Copper(I) oxide                                                                       M1                                                                              160                                                                              1.0                                                                              79     90                                 27                                                                              3,5-Dimethylphenyl                                                                      p-tert-                                                                            3.0                                                                              Copper(I) oxide                                                                       M1                                                                              160                                                                              1.0                                                                              77     90                                             Butyl-                                                                        phenoxy                                                           __________________________________________________________________________

These are analytical data for the imides of Examples 23, 24 and 26.

Example 23 N-(4-Phenylazophenyl)perylene-3,4-dicarbimide

red powder of m.p. >360° C.;

Elemental analysis (% by weight calc./obs.): C: 81.4/80.8; H: 3.8/3.7;N: 8.4/8.3; O: 6.4/6.9; Mass (EI): m/z=501 (M⁺), 396 (M⁺ -PhN₂ ; 100%);IR (KBr): ν=1688 (s, C═O), 1650 (s, C═O) cm⁻¹ ; UV/VIS (H₂ SO₄): λ_(max)(ε)=413 (27691), 577 (27227), 614 (140738) nm.

Example 24 N-(3,5-Dimethylphenyl)perylene-3,4-dicarbimide

reddish orange crystals of m.p. >360° C.;

Elemental analysis (% by weight calc./obs.): C: 84.7/84.5; H: 4.5/4.5;N: 3.3/3.3; O: 7.5/7.6; Mass (EI): m/z=425 (M⁺ ; 100%); IR (KBr): ν=1695(s, C═O), 1653 (s, C═O) cm⁻¹ ; UV/VIS (CHCl₃): λ_(max) (ε)=265 (29378),487 (30930), 510 (29375) nm; ¹ H-NMR (300 MHz, CDCl₃): δ=8.57 (d, 2H);8.47 (t, 4H); 7.94 (d, 2H); 7.71-7.64 (dd, 2H); 7.15 (s, with nuclearcoupling, 1H); 6.94 (s, 2H) ppm.

Example 26 N-(3,5-Dimethylphenyl)-1,7-diphenoxyperylene-3,4-dicarbimide

blackish violet crystals of m.p. 125°-127° C.;

Elemental analysis (% by weight calc./obs.): C: 82.7/82.5; H: 4.5/4.5;N: 2.3/2.3; O: 10.5/10.6; Mass (EI): m/z=609 (M⁺ ; 100%), 517 (M⁺ -OPh;58%); IR (KBr): ν=1703 (s, C═O), 1670 (s, C═O) cm⁻¹ ; UV/VIS (NMP):λ_(max) (ε)=361 (7863), 516 (52443), 742 (722) nm.

B) Purification of perylene-3,4-dicarbimides of the formula Ib ##STR11##Examples 28 to 33

A mixture of x g of the crude product of Example 7 (12; 14; 16; 22; 25)and 100 g of N-methylpyrrolidone (NMP) was heated at 165° C. for 15 minwith stirring, then cooled down to 50°-55° C. with slow stirring andfinally down to room temperature without stirring. The precipitated NMPadduct was filtered off, successively washed with 28 g of NMP, 22 g ofethanol and 68 g of 6% strength by weight hydrochloric acid, thensuspended in water, again filtered off, washed neutral with water anddried under reduced pressure.

The dried NMP adduct was comminuted and heated in a mixture of 1500 mlof isopropanol, 90.5 g of potassium hydroxide (85% strength) and 35 mlof water under reflux (about 82° C.) for t h. After cooling at 25° C.,the precipitate was filtered off, washed successively with isopropanol,a little methanol and water, subsequently suspended in 100 ml of 5%strength by weight hydrochloric acid, again filtered off, washed neutralwith water and dried under reduced pressure.

Further details of these experiments and their results are listed inTable 4.

                                      TABLE 4                                     __________________________________________________________________________                         Yield in %                                                            Crude    based on                                                             product of                                                                            crude                                                    Ex.                                                                             R.sup.1                                                                             R.sup.2                                                                         x g                                                                              Ex.  t h                                                                              product!                                                                           Purity in %                                                                         Appearance                                                                           m.p. °C.                        __________________________________________________________________________    28                                                                              2,6-Diiso-                                                                          H 15.7                                                                              7   10.0                                                                             89   >99   luminous red,                                                                        >300                                     propylphenyl                  crystalline                                   29                                                                              Phenyl                                                                              H 15.0                                                                             12   5.5                                                                              79   >98   brownish red,                                                                        >360                                                                   amorphous                                     30                                                                              2-Methyl-                                                                           H 15.0                                                                             14   6.0                                                                              83   >99   dark red,                                                                            >360                                     phenyl                        crystalline                                   31                                                                              2-Pyridyl                                                                           H 15.0                                                                             16   10.0                                                                             71   >98   brownish red,                                                                        >360                                                                   amorphous                                     32                                                                              Octadecyl                                                                           H 15.0                                                                             22   4.0                                                                              87   >99   reddish orange,                                                                      175-176                                                                amorphous                                     33                                                                              2,6-Diiso-                                                                          Br                                                                              15.0                                                                             25   7.0                                                                              85   >98   reddish violet,                                                                      >300                                     propylphenyl                  amorphous                                     __________________________________________________________________________

These are analytical data for the purified imides.

Example 28 N-(2,6-Diisopropylphenyl)perylene-3,4-dicarbimide

¹ H-NMR (300 MHz, CDCl₃): δ=8.60 (d, 2H); 8.37 (d, 2H); 8.35 (d, 2H);7.85 (d, 2H); 7.58 (t, 2H); 7.4-7.5 (dd, 1H); 7.33 (d, 2H); 2.77 (m,2H); 1.18 (d, 12H) ppm; ¹³ C-NMR (75.5 MHz, CDCl₃): δ=164.0; 145.7;137.5; 134.3; 131.9; 131.1; 130.9; 130.5; 129.4; 129.2; 127.9; 127.0;124.0; 123.8; 121.0; 120.1; 29.1; 24.0 ppm; IR (KBr): ν=1696 (s, C═O),1656 (s, C═O) cm⁻¹ ; UV/VIS (CH₂ Cl₂): λ_(max) (ε)=263 (33565), 484(33241), 506 (32061) nm.

Example 29 N-Phenylperylene-3,4-dicarbimide

Mass (EI): m/z=397 (M⁺ ; 100%) IR (KBr): ν=1698 (s, C═O), 1651 (s, C═O)cm⁻¹ ; UV/VIS (NMP): λ_(max) (ε)=354 (2890), 498 (29638) nm.

Example 30 N-(2-Methylphenyl)perylene-3,4-dicarbimide

Mass (EI): m/z=411 (M⁺), 394 (M⁺ +H-H₂ O; 100%); IR (KBr): ν=1682 (s,C═O), 1652 (s, C═O) cm⁻¹ ; UV/VIS (NMP): λ_(max) (ε)=355 (3223), 503(32014) nm.

Example 31 N-(2-Pyridyl)perylene-3,4-dicarbimide

Mass (FD): m/z=398 (M⁺ ; 100%); IR (KBr): ν=1700 (s, C═O), 1654 (s, C═O)cm⁻¹ ; UV/VIS (NMP): λ_(max) (ε)=352 (2541), 501 (30328) nm.

Example 32 N-Octadecylperylene-3,4-dicarbimide

¹ H-NMR (250 MHz, CD₂ Cl₂): δ=8.37 (d, 2H); 8.25 (d, 2H); 8.19 (d, 2H);7.77 (d, 2H); 7.50 (t, 2H); 4.05 (t, 2H); 1.15-142 (m, 32H); 0.81 (t,3H) ppm; Mass (FAB): m/z=573 (M⁺), 321 (M⁺ -C₁₈ H₂₅ ; 100%); IR (KBr):ν=1680 (m, C═O), 1649 (s, C═O) cm⁻¹ ; UV/VIS (H₂ SO₄): λ_(max) (ε)=410(6158), 574 (21297), 613 (168942) nm.

Example 33 N-(2,6-Diisopropylphenyl)-1,7-dibromoperylene-3,4-dicarbimide

Mass (EI): m/z=642/640/638(M⁺, ⁷⁹ Br/⁸¹ Br), 560/558 (M⁺ -Br; 100%); IR(KBr): ν=1695 (s, C═O), 1656 (s, C═O) cm⁻¹ ; UV/VIS (H₂ SO₄): λ_(max)(ε)=399 (13521), 548 (41551) nm.

We claim:
 1. A process for preparing perylene-3,4-dicarbimides byreacting a perylene-3,4,9,10-tetracarboxylic acid or the correspondinganhydrides with a primary amine, which comprises performing the reactionin a reaction medium consisting essentially of a tertiary nitrogen baseas solvent and of a transition metal or transition metal salt ascatalyst.
 2. A process as claimed in claim 1, wherein the tertiarynitrogen base used is a nitrogen-containing heteroaromatic.
 3. A processas claimed in claim 1, wherein the catalyst used is zinc, a zinc salt,copper, a copper salt or a mixture thereof.
 4. A process for purifyingperylene-3,4-dicarbimides obtained by reaction of aperylene-3,4,9,10-tetracarboxylic acid or of the correspondinganhydrides with a primary amine, which comprises first heating the crudeproducts in N-methylpyrrolidone, then treating the resultingN-methylpyrrolidone adducts with a base in the presence of an organicdiluent, and, if desired, subjecting the subsequently isolated productsto an additional treatment with an aqueous acid.
 5. A process as claimedin claim 4, wherein the base used is an alkali metal hydroxide or analkali metal alkoxide.
 6. A process for making pureperylene-3,4-dicarbimides by reacting aperylene-3,4,9,10-tetracarboxylic acid or the corresponding anhydrideswith a primary amine, which comprises performing the reaction in thepresence of a tertiary nitrogen base as solvent and of a transitionmetal or transition metal salt as catalyst and first heating theresulting crude products in N-methylpyrrolidone, then treating theresulting N-methylpyrrolidone adducts with a base in the presence of anorganic diluent, and, if desired, subjecting the subsequently isolatedproducts to an additional treatment with an aqueous acid. 7.Perylene-3,4-dicarbimides of the general formula Ia ##STR12## whereR^(1') is C₁₄ -C₃₀ -alkyl whose carbon chain may be interrupted by oneor more of --O--, --S--, --NR³ --, --CO-- and/or --SO₂ -- and which ismonosubstituted or polysubstituted by carboxyl, sulfo, hydroxyl, cyano,C₁ -C₆ -alkoxy or a 5-, 6- or 7-membered heterocyclic radical which isattached via a nitrogen atom and which may contain further heteroatomsand may be aromatic, where R³ is hydrogen or C₁ -C₆ -alkyl; or R^(1') isC₅ -C₈ -cycloalkyl whose carbon skeleton is interrupted by one or moreof --O--, --S--, and/or --NR³ --; or R^(1') is phenyl which ispolysubstituted by C₁ -C₄ -alkyl or methoxy at least in the two orthopositions, and/or monosubstituted or polysubstituted by C₅ -C₁₈ -alkyl,C₂ -C₆ -alkoxy, halogen, hydroxyl, cyano, carboxyl, --CONHR⁴, --NHCOR⁴and/or aryl- or hetaryl-azo, which may each be substituted by C₁ -C₁₀-alkyl, C₁ -C₆ -alkoxy, halogen, hydroxyl, cyano or carboxyl, where R³is as above defined, and R⁴ is hydrogen, C₁ -C₁₈ -alkyl, aryl orhetaryl, wherein the aryl or hetaryl may each be substituted by C₁ -C₆-alkyl, C₁ -C₆ -alkoxy, halogen, hydroxyl or cyano, or R^(1') isnaphthyl or hetaryl, which may each be substituted by a radical definedas substituents for phenyl, in which case the C₁ -C₄ -alkyl and C₁ -C₆-alkoxy substituents may be in any desired position on the ringsystem;R² is in each instance independently of the other instanceshydrogen; halogen; C₁ -C₁₈ -alkyl; aryloxy, arylthio, hetaryloxy orhetarylthio, which may each be substituted by C₁ -C₁₀ -alkyl, C₁ -C₆-alkoxy, cyano or carboxyl.
 8. Perylene-3,4-dicarbimides as claimed inclaim 7 of the formula Ia whereR^(1') is C₁₄ -C₃₀ -alkyl which ismonosubstituted by carboxyl, sulfo, hydroxyl or a 5-, 6- or 7-memberedheterocyclic radical which is attached via a nitrogen atom and which maycontain further heteroatoms and may be aromatic; phenyl which ispolysubstituted by C₁ -C₄ -alkyl at least in the two ortho positions, ormonosubstituted or polysubstituted by halogen, hydroxyl, cyano,carboxyl, --COHNR⁴ or --NHCOR⁴ and/or monosubstituted by aryl- orhetaryl-azo, which may each be substituted by C₁ -C₁₀ -alkyl, C₁ -C₆-alkoxy, halogen, hydroxyl, cyano or carboxyl; hetaryl which may besubstituted by the radicals defined as above substituents for phenyland/or by C₁ -C₄ -alkoxy, in which case the C₁ -C₄ -alkyl substituentsmay be in any desired position on the ring system; R² is in eachinstance independently of the other instances hydrogen, halogen orphenoxy which may be substituted by C₁ -C₆ -alkyl, C₁ -C₆ -alkoxy, cyanoor carboxyl.
 9. Perylene-3,4-dicarbimides as claimed in claim 7 of theformula Ia where R^(1') is C₁₄ -C₃₀ -alkyl which is monosubstituted bycarboxyl, sulfo or hydroxyl; phenyl which is substituted by C₁ -C₄-alkyl in both ortho positions, hydroxyl, cyano, carboxyl, --CONHR⁴ or--NHCOR⁴, where R⁴ is C₁ -C₄ -alkyl or phenyl which may be substitutedby C₁ -C₄ -alkyl, C₁ -C₄ -alkoxy or cyano, or by phenyl- or naphthyl-azowhich may be substituted by C₁ -C₄ -alkyl, C₁ -C₄ -alkoxy, hydroxyl orcyano; monocyclic hetaryl which may be monosubstituted orpolysubstituted by C₁ -C₄ -alkyl, C₁ -C₄ -alkoxy, hydroxyl or cyano ormonosubstituted by phenyl- or naphthyl-azo which may be substituted byC₁ -C₄ -alkyl, C₁ -C₄ -alkoxy, hydroxyl or cyano;R² is in each instanceindependently of the other instances hydrogen or phenoxy which may besubstituted by C₁ -C₄ -alkyl.
 10. A method of coloring comprisingcontacting the perylene-3,4-dicarbimides of the formula Ia as set forthin claim 7 with an organic or organic/inorganic composite material.